The idea is interesting, but I'm unsure how it is sustainable.  I know in countless contexts, even eBay, that most people are very inclined towards overpricing if given a chance.  Accordingly, the chance that node operators will agree to a reasonable transaction fee reduction in the future seems very iffy, as they would have to willingly give up money.  Sure, they might gain more money in the long view later on by doing so, but trying to get people to actually act so can be difficult.  

I could easily see XtraBytes stuck at 100 coins per transaction essentially permanently, while the coin eventually stagnated by accordingly having no regular users other than speculators.  Of course, "no regular users other than speculators" does describe most altcoins in general, but scalability seems low.